SQL Group By Example | Group By Clause In SQL Tutorial is today’s
topic. The GROUP BY clause in SQL is used to arrange the same
data into groups with the help of some functions. The GROUP BY
clause group rows that have the same values into summary rows,
like “find the number of customers in each city.” The Group By
statement allows you to arrange the rows of a query in the groups. The groups are
determined by the table columns that you specify in a
GROUP BY clause.

SQL Group By Example

The GROUP BY statement is also used with the aggregate functions
(COUNT, MAX, MIN, SUM, AVG) to group the result by one or more
columns. Its main work is to summarize the data
from the database. If you want to build some kind of chart then
the GROUP BY clause will be …

The world seems awash in unstructured, NoSQL data, mainly of the
JSON variety. While this has a great many benefits as far
as data mutability and not being locked into a rigid structure
there are some things missing that are common in the structured
world of SQL databases.

What if there was a way to take this unstructured NoSQL JSON data
and cast it, temporarily, into a structured table? Then you
could use all the processing functions and features found in a
relation database on you data. There is a way and it is the
JSON_TABLE function.

JSON_TABLE
You can find the documentation for JSON_TABLE here but there are some examples below
that may make learning this valuable function easier than the
simple RTFM.

SQL Left Join Tutorial With Example | Left Outer Join in SQL is
today’s topic. The LEFT JOIN keyword returns all records from the
left table (table1), and the matched records from the right table
(table2). The LEFT JOIN clause allows us to
query data from the multiple tables. It
returns all the rows from a left table and the matching rows from
a right table. This means that the left join returns all the
values from a left table, plus matched values from a right table
or NULL in the case of no matching join predicate.

MySQL Server generates several logs that can help you monitor the activities of
the server. However, once these logs are enabled, they can grow
in size and start taking up too much disk space. This is why it’s
important to have an automated way of archiving and preserving
MySQL log files for a certain duration, as well as deleting the
old ones. In this blog post, we describe some best practices for
setting up and managing MySQL error logs, general logs and slow
query logs for your MySQL deployments.

Setting Up MySQL Server Logging

Let’s look at how to setup the following 3 types of logs:

Error Log

Logs all the problems encountered during starting, running, or
stopping mysqld. This log can be enabled by having the following
option in /etc/my.cnf file:

SQL Update Query Example | SQL Update Statement Tutorial is
today’s topic. The SQL UPDATE statement is used to modify the
existing records in a table. You need to be very careful when
updating records in a table. SQL WHERE clause in the UPDATE statement
specifies which record(s) that should be updated. If you omit the
WHERE clause completely, then all records in the table will be
updated!

SQL Update Query Example

You need to specify which record needs to be updated via WHERE
clause, otherwise all the rows would be affected. We can update
the single column as well as multiple columns using the UPDATE
statement as per our requirement.

SQL SELECT Query Example | SQL SELECT Statement Tutorial is
today’s topic. The Select is the most commonly used statement in
SQL. SQL SELECT statement is used to fetch the data from a
database table which returns this data in the form of a result
table.

The Select command in SQL is one of the most powerful and
heavily used commands. This is I guess the first command anyone
learns in SQL even before CREATE which is used to create a table
in SQL. SELECT is used in SQL to fetch records from
database tables, and you can do a lot many things using Select.

For example, you can select all records; you can choose few
records based on the condition specified in WHERE clause, select
all columns using the wild card (*) or only selecting a few
columns by explicitly declaring them in a query.

SQL Where Clause Example | SQL Where Query Tutorial is today’s
topic. The WHERE clause is used to filter the database records.
The WHERE clause is used to extract only those records that
fulfill the specified condition. The
SQL WHERE clause is used to specify the
condition while fetching the data from a single table or by
joining the multiple tables. If a given condition is satisfied,
then only it returns the specific value from the table. You
should use a WHERE clause to filter the records and fetching the
necessary records.

SQL Where Clause Example

The WHERE clause is not only used in the SELECT statement; it is
also used in an UPDATE, DELETE statement. The syntax of a SELECT
statement with a WHERE clause is following.

SQL Insert Query Tutorial | SQL Insert Into Statement Example is
today’s topic. If you are not familiar with creating a table in
SQL, then please check out my how to create a table in SQL tutorial. The
INSERT INTO statement is used to add new values into the
database. The INSERT INTO statement adds the new record to the
table. INSERT INTO can contain the values for some or all of
its columns. INSERT INTO can be combined with a SELECT to insert
records.

SQL Insert Query Tutorial

The general syntax of SQL INSERT INTO
Statement is following.

INSERT INTO table-name (column-names)
VALUES (values)

Here, column-names could be column1, column2,
column3,…columnN are the names of the columns in a table into
which you want …

Introduction In this article, we are going to see how a
relational database executes SQL statements and prepared
statements. SQL statement lifecycle The main database modules
responsible for processing a SQL statement are: the Parser, the
Optimizer, the Executor. A SQL statement execution looks like in
the following diagram. Parser The Parser checks the SQL statement
and ensures its validity. The statements are verified both
syntactically (the statement keywords must be properly spelled
and following the SQL language guidelines) and semantically (the
referenced tables and column do exist in the database). During...
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